An approximate method is presented that can be used to determine the non-li
near behaviour of a new structural bracing system called the 'Disposable Kn
ee Bracing'. In this framing system, a special form of diagonal brace conne
cted to a knee element instead of beam-column joint, is investigated. The d
iagonal element provides lateral stiffness during moderate earthquakes. How
ever, the knee element is designed to have three plastic joints for dissipa
tion of the energy caused by strong earthquake. This article demonstrates t
he transformation of a complex problem into a new, practical set of design
charts and graphs. First, by studying of the elastic behaviour of the syste
m, a suitable shape and angle for diagonal-knee bracing is proposed. Then,
by use of the main graphs and charts designed accordingly, the dynamic resp
onse of this model is properly investigated. Finally, the correctness of th
e results is ascertained, using an example problem. (C) 2000 Elsevier Scien
ce Ltd. All rights reserved.